1. Field of the Invention
The present invention relates to an image evaluation device and an image evaluation method for evaluating images based on faces contained in the images, and a program for causing a computer to carry out the image evaluation method.
2. Description of the Related Art
With widespread use of digital cameras and significant increase in capacity of recording media for storing images in recent years, users can store a lot of images in a single medium. However, it is troublesome for users to select an image(s) to be processed (to be printed, for example) from a large number of images. Therefore, in order to efficiently select such images, functions are demanded, such as for refining candidate images with certain conditions before users finally determine images to be printed and/or for selecting images that are suitable to be printed according to user's taste based on evaluation of images.
For example, Japanese Unexamined Patent Publication No. 2002-010179 discloses an approach in which images are evaluated based on any of lightness of the images, acceleration sensor values and AF evaluation, and pictures that are unsuitable to be printed are automatically excluded based on the results of the evaluation.
Further, Japanese Unexamined Patent Publication No. 2004-361989 discloses an approach in which the orientation of a human face contained in each image is determined, an evaluation value for each image is calculated based on the determined orientation, and a desired image is selected from a plurality of images based on the calculated evaluation values.
Furthermore, U.S. Patent Application Publication No. 20020181784 discloses an approach in which images are evaluated using results of total evaluation with respect to a plurality of evaluation items such as a ratio of a face in an image, whether eyes are open or shut, the orientation of a face, focus, blurring, lightness and the like.
As described above, various approaches have been proposed for evaluating images based on faces contained in the images. However, the approaches described in the above-mentioned patent documents simply calculate evaluation values with respect to evaluation items to evaluate images. Therefore, their results not always reflect subjective evaluation by actual viewers of the images, and the evaluation by the actual viewers may differ from the calculated evaluation of the images.